The present invention is related to systems and methods for decoding information, and more particularly to systems and methods for Viterbi detection.
A number of systems rely on Viterbi decoding to process information. For example, various transmission and data storage systems rely on Viterbi decoding to recover transmitted and stored information. In a typical scenario, a data set is encoded, and the encoded data set is then distributed in such a way that one or more errors are possibly introduced to the data set because of noise. The potentially corrupted data set is provided to a Viterbi decoder that operates to determine a most likely match for the potentially corrupted data set. Determination of the most likely match is done by selecting a path exhibiting the closest distance between the received input and a possible code. Using this process, one or more errors included in the received data set may be corrected. In another typical scenario, a data set is transmitted through a channel which introduces inter-symbol-interference (ISI) as well as other noise, and the Viterbi detector (i.e., decoder or equalizer) is used to cancel the ISI and recover the data set.
In some cases, an input received by the Viterbi detector is out of bounds indicating the occurrence of some level of signal corruption. In many existing Viterbi detectors, such aberrant inputs are simply processed using a process similar to other inputs. Such an approach provides an effective error correction scheme, however, the out of bounds inputs reduce the accuracy of the Viterbi detector output. Other approaches operate to saturate all out of bounds inputs in an effort to limit the effect of such inputs on the Viterbi processing. This process of globally saturating the input where an out of bounds condition is found may significantly degrade the performance of the Viterbi detector.
Hence, for at least the aforementioned reasons, there exists a need in the art for advanced systems and methods for decoding information.